Method and apparatus for screen printing contiguous designs on elongated strips of material

ABSTRACT

This disclosure is directed to a method and apparatus for screen printing contiguous or abutting designs on a continuous strip of web material. This is attained by cooperatively associating a dryer with the printing screen, whereby the screen and associated dryer are shifted relative to the printed portion of the material as the latter is indexed one repeat in the opposite direction so that the dryer is disposed in heat transfer relationship with the trailing marginal portion of the indexed print to dry the same prior to the repositioning of the printing screen onto the indexed material to effect the next adjacent printed portion; and in which position, the dryer is disposed in heat transfer relationship with the remaining portion of the preceding printed portion to complete the drying of the preceding printed portion. This invention further contemplates effecting the indexing of the material in the direction of repeat by advancing an endless printing blanket by relative movement of a sectionalized table or by a positive drive of an end roller over which the printing blanket is threaded.

United States Patent [191 Jaffa [111 3,752,070 [451 Aug. 14, 1973 METHOD AND APPARATUS FOR SCREEN PRINTING CONTIGUOUS DESIGNS ON ELONGATED STRIPS OF MATERIAL [75] Inventor: David Jafla, Fairlawn, NJ.

[73] Assignee: Precision Screen Machines Inc.,

Hawthorne, NJ.

[22] Filed: July 20, 1971 [21] Appl. No.: 164,296

{52] U.S. Cl. 101/123, l0l/129 [51] Int. Cl B41! 13/14, B65h 29/24 [58] Field of Search 101/121, 129, 123, 101/115 56] References Cited UNITED STATES PATENTS 2,309,914 2/1943 Montague 101/115 2,359,825 10/1944 Campbell.... 101/115 2,484,671 10/1949 Bauman 101/115 3,106,890 10/1963 Schmitt 101/123 3,199,447 8/1965 Jaffa et a]. 101/129 X 3.199.449 8/1965 Jaffa et al. 101/129 3,357,350 12/1967 .Iaffa et al. 101/123 3,505,951 4/1970 Gartrell l0l/129 X 3,538,846 11/1970 101/123 3,650,207 3/1972 Black l0l/ll5 Primary Examiner-Edgar S. Burr Attorney-Seidman and Fisher ABSTRACT This disclosure is directed to a method and apparatus for screen printing contiguous or abutting designs on a continuous strip of web material. This is attained by cooperatively associating a dryer with the printing screen, whereby the screen and associated dryer are shifted relative to the printed portion of the material as the latter is indexed one repeat in the opposite direction so that the dryer is disposed in heat transfer relationship with the trailing marginal portion of the indexed print to dry the same prior to the repositioning of the printing screen onto the indexed material to effect the next adjacent printed portion; and in which position, the dryer is disposed in heat transfer relationship with the remaining portion of the preceding printed portion to complete the drying of the preceding printed portion.

32 Claims, 18 Drawing Figures minim ms 1 4 ma suszrmnnq INVENTOR DA V/ D JAF FA 1 m w ATTORNEY PAIENIEDAUB 4873 SHEEI 02 0F 10 N H U. M E 0 Wm: IN D BY 4:04A

PATENIED 9 4 975 sum our 10 INVENTOR DAV/D JAF FA M ATTORNEY PAIENIHI 3.752.070

sum as nr 10 T In 1- '1'. I ll, 64 r r I, 65

I J 2 II J INVENTOR DAV! D JAF FA BY a d M ATTORNEY PAIENIEW Q 3.752.070

sum 01 nr 10 INVENTOR DAV/ D JAF FA ATTC R N EY Pmemmmmma 3.752.070 SHEET us ur 1o' 5 INVENTOR DAV/D JAFFA ATTORNEY PATENIEB M18 4 B75 SHEET 08 W10 RAH D mguimg ng WW. m 4 D WM M M l minnow-1m sum 10 0F 10 INVENTOR DAV/ D JAF F A BY lximqsv METHOD AND APPARATUS FOR SCREEN PRINTING CONTIGUOUS DESIGNS ON ELONGATED STRIPS OF MATERIAL PROBLEM AND PRIOR ART Heretofore considerable difficulty had been encountered in enhancing or speeding up screen printing cycles for forming continuous or contiguous designs on a continuous sheet of web material, e.g., screen printing wall paper and/or the like. The difficulty encountered in screen printing continuous patterns on paper is than the preceding design or pattern must be completely dry before the next succeeding pattern can be printed. This is because the printing screen utilized in screen printing successive designs must necessarily overlap a portion of the preceding design in order to provide for proper registration between succeeding designs or print repeats. Unless the marginal portion of the preceding print was dried prior to the making of the next succeeding'print, the overlapping portion of the screen invariably would result in smearing or smudging of the marginal portion of the preceding print. The problem is particularly aggrevated in jog printing of successive designs; i.e., where the design of one repeat is so formed so that it interlocks with a complementary jog" of the next succeeding print.

Heretofore scren printing continuous designs on paper was accomplished by double indexing the material in order to position the printed portion in a position where it can be dried. After drying the printed portion of the material had to be back indexed in order to place the material back under the printing screen to effect the next succeeding adjacent print. Thus the double indexing system required time consuming cycles which tended to increase the chance of error in registration.

Another difficulty which has been noted in the past is that when screen printing was performed on segmented tables having relatively movable surfaces for effecting the indexing of the indexing of the material, the spaces or gaps between adjacent table segments adversely affected the printed design. Also should any unevenness occur between the plane of the respective segmented tables, an unsatisfactory print would result.

OBJECTS It is therefore an object of this invention to provide an improved method and apparatus for minimizing the time interval of an operating cycle for screen printing successive continuous designs or repeats on' a continuous sheet of web material.

Another object is to provide a screen printing method and apparatus in which a portion of a printed design is being dried as the material is indexed one repeat, and whereby the remaining portion is being dried as the next succeeding design is being screen printed on the material.

Another object is to provide a method and apparatus in which the trailing portion of a scrcen printed design is first dried as the material is indexed, and the remaining leading portion of the design being dried during the printing interval of the next succeeding print.

Another object is to provide a screen printing apparatus having a uniform supporting surface for the web material.

Another object is to provide a screen printing apparatus having a plurality of printing stations each having drawing relative vacuum or negative pressures altera dryer for effecting a two step drying of a preceding printed design.

Another object is to provide a method and apparatus for effecting screen printing continuous designs on non-porous con-tinuous sheets in a positive, effective and rapid manner.

Another object is to provide an improved indexing arrangement for effecting the repeat of the printed material.

BRIEF SUMMARY OF THE INVENTlON This invention is directed to a method and apparatus for screen printing sequential complementary designs on a continuous strip of material. The method comprises the steps of positioning a printing screen having a stencilled design portion disposed between opposed well portions and an associated squeegee into printing position onto the material to be printed. The printing of the material is effected by relative movement between squeegee and the stencilled portion of the screen. Upon completion of the printing stroke, the screen and the associated squeegee are raised off the material to a non-printing position. The printed portion of the material is then indexed a predetermined distance in the direction of repeat as the printing screen and the associated squeegee, disposed in the nonprinting position, is moved a predetermined amount relative to the indexing of the printed portion of the material to effect the drying of the-trailing edge portion of the printed material. The relative movement of the printing screen and associated squeegee and the indexing of the printed material results in exposing the printed portion of the material to a dryer which is connected to the screen to move therewith. Upon drying of the trailing edge portion of the printed material, the screen and associated squeegee is returned to its initial printing position for effecting the printing of the next adjacent repeat, as the associated dryer is repositioned over the undried portion of the printed portion to effect the drying thereof while the next succeeding print is being formed. Upon the printing of the next succeeding print, the cycle of operation is repeated.

The foregoing method may be automated or mechanically accomplished by an apparatus comprising a frame having supported thereon table means constructed to include a first portion fixed to the frame and a second portion operatively connected for reciprocal movement relative to the fixed table portion. Each of the table portions includes adjacent co-planar perforated table tops operatively connected to a vacuum chamber which is connected to a vacuumpump for nately on each of the table portions. The respective table portions are hingedly;connected in a manner to facilitate. the relative adjustment therebetween for maintaining the respective table tops co-planar without interfering with the relative reciprocal, movement therebetween. A table drive means is operatively connected to the movable portion of thetable means for effecting the movement thereof relative to the first table portion. Supported over the table surfaces is the upper flight of an endless printing blanket which forms the support for the continuous strip of material to be printed. The printing blanket is also provided with a series of perforations to communicate with the perforations in the table tops so that the material supported thereon can be held in position thereon whenever the vacuum for a particular table section is actuated. The arrangement is such that by alternately actuating the vacuum means of the respective table tops and effecting relative movement therebetween the material to be printed can be readily indexed in the direction of repeat.

Movably mounted on the frame is a printing head which includes an upper head assembly and a lower head assembly. The lower head assembly is mounted on the frame for movement between a lowered printing position and a raised non-printing position with the upper head assembly mounted on the lower head assembly for relative reciprocal movement with respect to the lower head assembly. The connection between the lower head assembly and the frame comprises elevating means which when actuated effect the raising and lowering of the printing head relative to the frame between a printing and non-printing position.

One or more printing screen is mounted on the upper head assembly for movement therewith between a printing and non-printing position and for relative reciprocal movement relative to the table indexing means. A squeegee means is operatively associated with each of the respective screens for effecting the printing stroke when the printing head and associated screen and squeegee are moved into printing position.

A drying means is connected in tandem with each printing screen to reciprocate therewith as the upper head assembly is moved relative to the lower head assembly. Means are also operatively connected to the drying means for effecting the pivoting of the dryer means between an operative and an inoperative position, the dryer means being pivoted to an inoperative position whenever the operation of the screen printing machine is stopped for any reason.

A printing head drive means is operatively connected to the printing head for effecting reciprocal movement of the upper printing head assembly. The screen and associated squeegees carried thereon, and the connected dryer means are moved relative to the direction of repeat of the material so that the trailing edge portion of a preceding printed portion of the material can be exposed in heat transfer relationship with the dryer means to dry a portion of the printed material prior to the printing of the next succeeding print.

After a lapse of a predetermined drying interval, the printing head, its associated screen, squeegee and dryer means are moved to the initial position whereupon the printing screen and associated squeegee are lowered into printing position to effect the print of the next succeeding abutting design. in the printing position the dryer is disposed in drying relationship to the leading portion of the preceding printed design to efi'ect the final drying thereof as the next succeeding print is being performed; the cycle of operation being thereafter repeated.

This invention further contemplates a modified indexing means wherein the printing blanket is indexed by effecting a positive drive on an end roller over which the printing blanket is threaded.

FEATURES A feature of this invention resides in the provision of a method and apparatus for performing a screen printing cycle for effectively printing a continuous design on an elongated strip of material in a manner which prohibits any smearing of the design in the vicinity of registration between adjacent designs or repeats.

Another feature of this invention resides in a method and apparatus wherein the trailing edge portion of a preceding printed design is positively dried before the next adjacent design segment is printed without skip indexing.

Another feature of this invention resides in the provision of an apparatus for effecting the continuous printing of a design on an ,=elongated sheet of material wherein a portion of a preceding printed design is dried on indexing of the material and whereupon the remaining portion of the preceding design is dried during the printing of the next succeeding design or repeat.

Another feature of this invention resides in the provision of a method and apparatus wherein the time interval of a printing cycle of successive repeats of a continuous design on a sheet of material is substantially reduced.

Another feature of this invention resides in a screen printing apparatus in which relative movement of the supporting table means and associated printing blanket is utilized to effect the indexing of a continuous strip of material subsequent to each printing operation.

Another feature of this invention resides in the provision of a screen printing apparatus having a sectionalized supporting table with relatively movable portions utilized in conjunction with an endlessprinting blanket to define a uniform supporting surface for supporting the material to be printed thereon, and having adjusting means operatively connecting the respective sections for maintaining the tops thereof substantially coplanar.

Another feature of this invention resides in the provi- 'sion of a screen printing apparatus having the printing head with a screen and associated dryer connected to move relative to the indexing of the printed material to expose the preceding printed portion of the material to the connected dryer as the material is indexed, and whereupon the return of the printing screen to its initial printing position will expose the remaining portion of the preceding print to the heating influence of the connected dryer as the next succeeding print is being performed.

Another feature of this invention resides in the provision wherein a plurality of printing stations and associated drying means are operatively carried on a printing head to effect a multi-colored screen printing of successive designs on a continuous strip of material without'skip indexing.

Another feature of this invention resides in the provision of effecting the indexing of the printing blanket by a positive drive of the end roller over which the blanket is threaded.

Another feature of this invention resides in the provision of a method and apparatus in which the size of the I dryer utilized for effecting the drying of a printed design is of a size smaller than the overall size of the printed design.

Another feature of the invention resides in the provision of a method and apparatus by which the screen printing cycle is substantially enhanced so as to result in a substantial reduction of unit cost of screen printing a given design or repeat.

Other features and advantages will become more readily apparent when considered in view of the drawing and specifica-tion in which:

FIG. I is a plan view of an apparatus embodying the present invention having portions thereofbroken away.

FIG. 2 is a side elevation view of the apparatus of FIG. 1.

FIG. 3 is a sectional view shown to an enlarged scale taken along line 33 on FIG. 1.

FIG. 4 is a plan view of the frame assembly of the apparatus of FIGS. 1 to 3.

FIG. 5 is a side elevation view of the frame assembly of FIG. 4.

FIG. 6 is a side elevation view of the printing head portion of the frame assembly of FIGS. 4 and 5.

FIG. 7 is a detailed elevation view illustrating the connection between the printing head and the printing head carriage.

FIG. 8 is a detailed sectional view of the printing head taken along line 8-8 on FIG. 2.

FIG. 9 is a detailed sectional view of the screen holding assembly.

FIG. 10 is a detailed side elevation view of the dryer means operatively associated'with each of the printing screens.

FIG. 1 l is a detailed fragmentary front sectional view of the dryer means of FIG. 10.

FIG. 12 is an enlarged sectional detail view of the table means.

FIG. 13 is a side elevation view of a modified form of .the invention illustrating an alternate indexing means.

FIG. 14 is a fragmentary end view of FIG. 13.

FIG. 15 is a sectional view taken along line 15-15 on FIG. 13.

FIG. 16 is a cross sectional view of the modified embodiment of the apparatus of FIGS. 13 to 15.

FIG. 17 is a detail of the rack assembly utilized in the modified embodiment of FIGS. 13 to 16.

FIG. 18 is an enlarged detail of the cross-sectional view of the table construction of the modified embodiment of FIGS. 13 to 16.

DETAILED SPECIFICATION This invention is directed to a method of screen printing a continuous design on an elongated strip of material for making wallpaper and/or the like. It will be understood that the method to be described may be applied to screen printing either a non-porous material, as for example, paper, sheet plastic material and the like, or may be applicable to screen printing porous material, as for example a fabric. However, for the purpose of describing the invention reference will be made to the method and apparatus as applied to the screen printing of a non-porous material, as for example, pa-' per, sheet plastic and the like.

Also as defined herein a repeating design or continuous design is intended to include the printing of a predetermined design in succeeding sections and/or repeating a given design several times upon a continuous strip of material wherein each print is contiguously disposed to the preceding print either in abutting and/or jogging relationship. Jogging is herein defined as the joining or the continuation of succeeding prints in which the adjoining edge of one print complements the adjoining edge of the next adjacent print in an interlocking relationship.

The improved method of this invention comprises the steps of supporting a section of a continuous sheet of material, 20, e.g. a non-porous sheet of paper or plastic, drawn from a continuous source of supply 21 onto a printing blanket 22 by which the material is indexed from print to print. A printing screen 25 having a stencilled or printed portion disposed between opposed well portions and an associated squeegee 26 is placed into printing position onto the material 20. With the screen, material, and printing blanket held fast with respect to each other, the printing stroke is effected by transversing the squeegee 26 relative to the stencilled portion of the screen 25.

Upon transversing the printing stroke, the squeegee 26 and associated screen 25 are sequentially raised to a non-printing position above the material printed. With the screen 25 and squeegee 26 raised above the material in a non-printing position, the printing blanket 22 and the printed material 20 held fast thereto is indexed in the direction of repeat a pre-determined dis-' tance equal to the repeat distance.

The printing screen 25 operatively associated with a dryer 27 in the non-printing position is then shifted relative to the indexed portion of the printed material a distance sufficient to locate the associated dryer 27 in heat transfer relationship to a portion of the printed material adapted to abut the next succeeding print. The dryer 27 is maintained in drying relationship to this portion of the indexed print for a period of time to effect the drying thereof. Upon the lapse of drying time the printing blanket 22 is returned to its initial position as the printed portion of the material 20 thereon is held fast in the indexed position thereof. As the printing blanket 22 is being returned to its initial position and is being moved relative to the printed index portion of the materiaLthe printing screen 25,associated squeegee 26 and connected dryer 27 are shifted back to their respective initial positions. With the screen, squeegee and associated dryer returned to their respective initial positions the printing screen and associated squeegee are lowered into printing position onto the material to effect the next adjacent or succeeding print. The dryer associated with the screen during the printing of the next succeeding design is disposed in heat transfer relationship relative to the undried portion of the preceding print to complete the drying thereof. Because the abutting portion of the preceding print was effectively dried during the indexing step of that print, the portion of the screen tending to overly this dry portion during the next succeeding printed operation will not result in any smearing or smudging of the preceding print.

As shown in the drawings the apparatus comprises a frame means 30 defined in part by a pair of opposed longitudinally extending lower base members 31 in the form of structural angled members extending along the length of the frame. A plurality of supporting structural feet 32 are longitudinally spaced along the depending flange of the base member 31 to define the means by which the frame is supported on a supporting floor. Connected at spaced intervals to the upper flange of the respective base members 31 are a plurality of vertical uprights 33 which are interconnected by a transversely extending support beam 34. Opposed longitudinal upper side members 35-35 in the form of a structural angled member interconnect the respective uprights 33 and the interconnected support beam 34 together.

As best seen in FIG. 3 a table means 23is mounted 1 above the respective supporting beams 34. The support superstructure 37 for the table means 23 comprises a pair of opposed centrally extending I beams 38-38 which are supported on the transverse support beams 34. The table supporting superstructure also include a plurality of spaced apart uprights 38A38A to define the side support for the table means 23. As will be hereinafter described, the respective side supports SSA-38A comprise angled members on which the table means is adjustably supported.

Referring to FIGS. 3 and 12 the table means 23 comprises a pair of spaced apart opposed stationary table sections 40 and 41 and a relatively movable intermediate table section 42 which is mounted on the frame for reciprocal movement relative to the opposed stationary table sections 40 and 41.

Each table section, 40, 41 and 42, is provided with a table top portion 40A, 41A and 42A respectively, having formed therein a series of perforations or openings 43. Beneath the respective table tops 40A, 41A, 42A, there is formed a vacuum chamber 40B, 41B, 428, each being suitably connected into communication with a source of negative producing pressure, as for example a vacuum pump 44, which is diagrammatically illustrated. The arrangement is such that each chamber 40B, 41B, and 42B beneath the respective table tops 40A, 41A and 42A may be evacuated so as to subject the adjacent table top to a negative pressure. As will be hereinafter described, the arrangement is such that the negative pressure induced on the respective movable table sections 42 and the stationary table sections 40 and 41 are alternately actuated. Also, as will be hereinafter described, a proportioning valve 44A is operatively associated with the vacuum pump operating on the respective table sections to proportion the degree of vacuum alternately pulled on the respective table sections so that a relative negative pressure is induced on the respective table portions. In other words, as will be hereinafter described, optimum results will be obtained by retaining a relative vacuum or negative pressure,as for example a -50 percent negative pressure, on the stationary table sections 40 and 41 as a substantially 100 percent negative pressure is being drawn on the movable table section 42 during an indexing operation, and conversely maintaining a comparable relative 10-50 percent negative pressure on the movable section when the stationary sections 40 and 41 are subjected to substantially 100 percent negative pressure as during the holding or printing operation. In this manner the sheet material, as will be hereinafter described, is always subjected to some holding force to prevent rela-' tive movement between the material and the printing blanket 22 as the vacuum holding: forces are alternately shifted between the respective table sections to hold the material in position thereon either during the printing or the indexing step. In this manner accurate registration is assured between successive prints as relative vmovement between the sheet being printed and the blanket 22 is prohibited.

Referring again to FIGS. 3 and 12, the movable table section 42 is reciprocally mounted on bearing rods 45 which are supported by brackets 45A connected to the I beams 38. Connected to the undersurface of the movable table section 42 are bearings 46 by which the movable table section 42 is slidably connected to the bearing rods 45.

A drive means is operatively connected to the movable table section 42 to effect relative reciprocation of table section 42 relative to the stationary portions 40 and 41. In the illustrated embodiment the table drive means comprises a piston and cylinder assembly 47. As shown, in FIG. 5 the cylinder portion 47A of the assembly 47 is suitably secured to the frame means and the piston and associated piston rod 478 is actuated by fluid pressure. The free end of the piston rod 47A is directly coupled to the movable table section 42 so that the movement of the table is directly responsive to the actuation of the piston and cylinder assembly 47. It will be understood that a suitable track mounted on the frame assembly will guide the movable table section as it reciprocates relative to the stationary table portions 40 and 41 as the table drive means 47 is actuated. It will be understood that the linear displacement of the movable table means is equal to the desired distance of repeat; and suitable adjusting means are operatively associated with the table drive assembly 47 to adjust the distance of repeat. Accordingly within the limits of the index adjustment, the desired distance or length of repeat can be readily adjusted.

To insure that the respective table tops 40A, 41A and 42A are maintained in substantially co-planar relationship at all times, anadjusting means is provided whereby the level of the respective stationary table tops 40A, and 41A can be rendered adjustable to the level of the movable table top 42A. As best shown in FIG. 12, each of the stationary table tops 40A, 41A adjacent the inboard edge thereof are provided with a hinge bracket 48 having a bifurcated end portion 48A for hingedly connecting about the table slide rod or hearing 45. The outboard edge of the respective stationary table surface 40A, 41A are provided with spaced apart brackets 49 having elongated slotted openings therein 49A by which the outboard edge of the table are adjustably secured to the upper side members 38A of the table superstructure 37. Accordingly it will be noted that the movable table section 42 and the inboard edge of the opposed stationary section are commonly supported on the slide rods 45 whereas the outboard edge of the respective stationary sections are vertically adjustable. Thus if for any treason the table tops of the respective table sections are not level, the adjustment provided will effect restoration of the co-planar relationship of the respective table tops 40A, 41A, and 42A.

Mounted adjacent each end of the frame assembly 30 and the table sections 40, 41, 42 supported thereon are a pair of end rollers 50 and 51 rotatably journalled on suitable end bearings. Stretched over the respective end rollers is an endless printing blanket 22 wherein the upper flight 22A of the blanket is supported by the table tops 40A, 41A and 42A of the table'means. The lower flight of the blanket 22B is guided over opposed end guide rollers 53 and 54. The printing blanket 22 is formed with a series of openings 55 extending through the surface thereof to effect communication with the openings 43 formed in the tops of the table sections. The blanket 22 is provided with a width sufficient to span the width of the table means, and as will be herein described defines the support for the continuous sheet of material 261 to be printed. As will be apparent the surface of the upper flight of the printing blanket 22A provides a smooth support for the material 20.

A printing head means 24 is mounted on the frame means for movement relative thereto. As best seen in FIGS. 3 and 8, the printing head means 24 comprises a lower printing head assembly 58 and an upper printing head assembly 59 which extends substantially the length of the frame 30. The printing head means 24 comprises an essentially rectangular shaped. structure which circumscribes the table means 23.

As best seen in FIGS. 3 and 8, the lower frame assembly 58 is defined by rectangularly disposed structural member 58A which is operatively connected to the frame means 30 for movement between a raised nonprinting position and a lowered printing position by means of a plurality of lifters 60 which are suitably connected to an elevating actuating means 61. The elevating actuating means 61 includes a piston and cylinder assembly, the cylinder 61A of which is mounted adjacent one end of the frame means as seen in FIG. 5. The piston 61B of cylinder assembly 61 is connected to one end of operating lever 62 which is fulcrummed at an intermediate point to the frame. The other end of lever 62 is connected to a linkage 63 which is suitably toggled to each of the lifters 60 of the lower head assembly. Accordingly, whenever the lifter piston and cylinder assembly 61 is actuated the reciprocation of the piston 61B is transmitted through the lever 62 and connected linkage 63 to operate the lifters 60 to raise and lower the lower printing head assembly 58.

The upper printing head assembly 59 is mounted on the lower head assembly 58 to move therewith. Also the upper head assembly is operatively connected to the lower head assembly for relative reciprocal movement. This is attained by longitudinally spacing a plurality of bearing rods- 64 along the opposed structural members 58A (See FIG. 8) of the lower head assembly. See also FIGS. 3 and 4. The bearing rods are supported in brackets 65 carried on members 58A. The structural members 59A defining the upper head assembly have connected thereto bearings 66 for slidably receiving the slide rods 64. The arrangement is such that the upper head assembly 59 can slide relative to the lower head assembly 58, as well as being moved between a raised and lowered position with the lower head assembly.

A drive means is operatively connected to the upper head assembly 59 for effecting the drive thereof relative to the lower head assembly. The printing head drive means 67 comprises a printing head carriage. 68 formed of structural members 68A which are mounted on bearings 69 movably supported on appropriate rail means 70. As best seen in FIGS. 6 and 7, the upper printing head 59 is provided with a connector 71 connected to one end thereof by which an associated connecting link 72 hooks to a pin 73 carried by the printing head carriage 68. Referring to FIG. 7, the connecting link 72 is mounted for vertical movement on the pin 73 to provide for the necessary raising and lowering of the printing head during an operating cycle of the apparatus as will be hereinafter described.

The actuating means for the printing carriage comprises a driving means in the form of a piston and cylinder assembly which includes a cylinder 740 connected to the frame and a piston rod 75D connected to the carriage structure 68A. Thus it will be apparent that whenever the actuating means or piston and cylinder assembly 74, 75 is actuated the carriage 68 and connected upper printing head 59 is reciprocated relative to the lower head assembly 58.

Mounted on the upper head assembly 59 are one or more printing screens 25. As best seen in FIG. l,a plurality of printing screens are supported in spaced relationship. Each screen 25 defines a printing station to effect a predetermined print. As is well known each screen 22 includes a frame 22A for supporting a printing screen having a stencilled portion 228 and opposed well portions. It will be understood that the number of screens 22 mounted on the printing head will be dependent upon the number of different colors needed to form a complete multicolored design. Thus a printing apparatus in accordance with this invention need not be limited to a single color print, and as many as four, five or more screens are practical.

Each screen 22 is supported on the upper printing head assembly 59 by a series of screen holding brackets 74 arranged to support each corner of a screen 22. Each screen holding bracket is similarly constructed. As best seen in FIG. 9, the screen holding bracket 74 includes an arm 74A which is adjustably connected by set screws 75, 76 to a screen holding rail 77 mounted on the printing head structure member 59A- The rail 77 extends along the length of the printing head assembly so that the screen holding bracket may be suitably secured anywhere therealong. Connected to the free end of arm 74A is a depending leg 748 to which there is supported a screen holding stud 88. The holding stud 88 is supported relative to the screen bracket 74 so as to provide a limited lost motion therebetween as the printing head is raised between a lowered printing position and a raised non-printing position. As will be hereinafter described the lost motion is to permit the squeegee to be raised above the screen 22vbefore the screen is raised off the material 20, as the printing head is moved from a printing position to a non-printing position. This is attained by loosely supporting the stud 88 in a pair of spaced lugs SSA-88B connected to bracket leg 74B. Connected to the stud 88 so am be disposed between the spaced lugs 88A-88B is a guide 78, and a coil spring 79 is interposed between the upper lug 76 and the guide 78. As will be hereinafter described the lost motion is attained by the spacing between the bottom lug 88B and the guide 78 normally present when the printing head is in the lowered printing position; as indicated in the dotted line showing. The upper end 88C of the stud defines a seat on which the screen support bracket 80 rests.

Operatively associated with each screen is a squeegee 26. Each squeegee 26 is operatively connected to a squeegee carriage 81 which is movably mounted for movement along a squeegee carriage rail 82 which is mounted along the inside of the upper printing head structural members 59A. Because the squeegee carriage 81 and associated squeegeeis mounted on the upper printing head assembly 59, it will be noted that the squeegee 26 will be raised between printing and non-printing position as the printing head assembly 59 is raised and lowered.

A squeegee drive means 83 is operatively connectedto the squeegee carriage to efie'ct the drive thereof for effecting the printing stroke. In the illustrated'embodi ment as shown in FIG. 4, the squeegee drive coprises a comprises and cylinder assembly which is mounted on the printing head carriage 67. The piston and cylinder assembly includes a double acting piston in which the associated piston rod 838 extends beyond each end of the cylinder 83A. The opposed ends of piston rod 838 in turn are connected to an endless flexible drive, e.g., a chain drive 84 which is threaded over suitable sprockets 84A, B, Cand D. One of the sprockets, e.g., sprocket 84D is journalled to a drive shaft 85 which is supported on suitable bearings adjacent one end of the machine frame. See FIG. 4.

On each end of the drive shaft 85 is a sprocket 86, 86 over which a driven chain 87 is threaded. Thus it will be noted a driven chain 87 is extended along each side of the frame.

The free ends of the driven chains 87 are operatively connected to the squeegee carriage means so that the latter is reciprocally moved to and fro in response to the actuation of the squeegee piston and cylinder drive means 83. For example, when the piston 83B of the squeegee drive assembly 83 is moved to the right as viewed in FIGS. 1, and 5, the squeegee 26 of an associated screen will move to the right relative to the screen to effect a printing stroke. When the piston rod 838 is moved to the left the squeegee 26 is returned to its initial position.

In accordance with this invention a dryer 27 is connected in tandem to each printing screen 25. As best seen in FIG. 1, a dryer 27 is interposed between adjacent screens 25.

Referring to FIGS. and II, the dryer assembly 27 comprises a carriage 90 which is mounted on wheels or rollers 91 arranged to be disposed in rolling engagement with rails 92 mounted on suitable rail supports 93 connected to the cross I beams 34. Pivotally mounted on the dryer carriage 90 is a heater platen 95. It will be understood that the platen 95 may be provided with a suitable heat source, e.g., infra-red heaters. A heater pivoting means 96 is operatively connected to the heater platen to effect the movement thereof between operative and inoperative position.

The heater pivoting means includes a piston and cylinder assembly 97 in which the cylinder 97A is pivoted at one end of the carriage 90. The free end of the piston 973 in turn is pivoted to the end of a link 98. The other end of link 98 is connected to the pivot or axle 99 about which the heater 95 pivots. Thus whenever the piston and cylinder assembly 97 is actuated, the arrangement is such that when the piston 97B is extended, the heater is pivoted to a raised inoperative position. When the piston rod 97B is retracted within the cylinder 97A, the heater platen 95 is pivoted downward toward operative position.

Referring to FIG. 10, one end of the heater carriage 90 is provided with a hitch 100 having an elongated slot 101 formed therein. Mounted in the slot 101 is a driving pin 102 for connecting the dryer carriage in driving relationship with the screen carriage or upper printing head assembly so that the dryer and its carriage will follow the reciprocal movement of the associated screen. It will be noted that the elongated slot 101 permits relative vertical movement of the screen 25 relative to the dryer carriage 90.

If desired a heat shield may be operatively associated with each dryer to contain the heat generated by the respective heaters. Also, if desired, a series of hot air jets may be operatively associated with each heater to assist the drying operation of a printed portion of the material 20. Also, if desired, a finishing heating platen 105 may be provided at the discharge end of the machine to insure complete drying of the finished printed material.

With the apparatus thus described the machine operation is as follows:

With the respective table tops adjusted and made level, a strip of material is placed onto the printing blanket 22. With the material positioned on the printing blanket 22, the vacuum pump is operated so aS to impart a relatively large vacuum pressure onto table sections to draw a negative pressure thereon. The vacuum or negative pressure thus produced, causes the printing blanket 22 and the material 20 supported thereon to be held fast against the table means 23. With the printing blanket 22 and material 20 thus held fast to the table means 23, the printing head 57 and associated screen 25 and squeegees 26 are lowered into printing position whereby the stencilled portion of the printing screen 25 is positioned directly onto the material to be printed. The lowering of the printing head 57 also causes the squeegees 26 to be lowered to engage the printing screen. The lowering of the printing head is effected by the actuation of the piston and cylinder assembly 61 operating the lifters 60. The squeegee drive means 83 is then actuated to effect the traversing of the squeegee 26 relative to its associated screen 22 to effect the printing stroke, whereby the squeegee forces the printing inks or dyes to flow through the stencilled portion of the screen to print the material 20.

Upon completion of the printing stroke, the elevating means or lifters 60 are actuated to effect the raising of the printing head 57 and associated screen and squeegees to a non-printing position. In doing so the squeegees 26 are first raised off the screen due to the lost motion built into the screen support bracket 74 whereupon continued vertical displacement of the printing head 57 causes the screen 22 to be then lifted off the material 20. With the screen 22 and squeegee 26 off the material the negative pressure on the stationary portions 40, 41 of the table means 22 is released as a negative pressure is drawn on the center portion 42 of the table 23. As this occurs the printing blanket 22 and the material are held fast to the movable portion 42 of the table means while the opposed portions of the blanket and material are made free to slide relative to the stationary table sections 40 and 41. For optimum results a lesser or relative negative pressure may be kept on the stationary table sections 40 and 41, as a full negative pressure is drawn on the movable section 42.

At this point of the cycle the piston and cylinder assembly 4 7 controlling the movement of the table section 42 is actuated to advance the table section 42 and the blanket 22 and material thereon in the direction of repeat, as for example, to the right as viewed in FIG. 1, causing the blanket 22 and material 20 to be indexed one repeat. As the blanket 22 and material is being indexed to the right as viewed in FIGS. 1 and 2, the printing head piston and cylinder assembly 74D is actuated to effect the shifting of the printing head 59 and the associated screen 25 and associated heater 27 to result in positioning the heater in drying relationship with a portion of the printed material that has been indexed. In the illustrated embodiment this is attained by shifting the screen and connected heater in a direction opposite to the direction of indexing. See FIG. 2 and 5, dotted line showing. Thus the heater carriage which is connected to the screen 25, causes the heater to be moved in the direction opposite to the direction of repeat a corresponding amount so that at the end of the indexing step, the heater 95 is disposed in drying relationship to the trailing edge portion of the index portion of printed material. With the heater disposed over the printed portion of the material for a dwell time of a few seconds, the trailing edge portion of the indexed print beneath the heater is dried.

Upon drying of this portion of the indexed print, the printing carriage, screen 25, and associated heater is returned to its initial position. At the same time the vacuum on the movable portion 42 of the table is released as the vacuum on the stationary portions 40 and 41 of the table means 23 is being drawn so that the printing blanket 22 and material 20 is held fast by the outer stationary portions 40 and 41 as the intermediate portion 42 of the table is returned to its initial position by sliding under the blanket held fast to the outer table section 40, 41. With the printing head 57 disposed in its initial position, the elevating means 60 are actuated to again lower the printing screen 25 and squeegee 26 into printing relationship onto the material for effecting the next adjacent print. Because the trailing edge portion of the preceding print had been dried, during the preceding indexing step, the portion of the screen overlapping the preceding print will not cause any smearing or blurring of the preceding print. Accordingly, the next succeeding print may be effected by repeating the printing cycle without a resulting smear occuring between the abutting margins of successive prints. I

As the next succeeding print is being formed, the dryer is positioned over the leading portion of the preceding print so that this portion of the preceding print can be dried as the printing of the next succeeding print is being performed. Upon the completion of the next succeeding print, the cycle is repeated.

With the method and apparatus described, it will be apparent that the overall operating cycle of the described screen printing operation can be reduced inasmuch as the drying of the given print is accomplished in two steps; namely a portion of the print is first dried upon the indexing of the print material, and the remaining portion of the indexed print being dried during the printing operation of the nextsucceeding print. Also the method and apparatus described facilitates the use of a smaller dryer as the drying of a print occurs in two steps, i.e., during the indexing of the printed material and during the printing of the next succeeding print. Consequently the dryer required, need be only approximately half the size of the given print, e.g., for a 36 inch repeat an 18 inch dryer can be utilized. Also the cycle of operation can be materially enhanced for the reason that the present method and apparatus obviates the need for skip indexing after each printing operation. Thus by minimizing the distance of repeat necessary to effect continuous printing of wallpaper, the greater the economy and accuracy of registration. Also it has been noted that optimum results can be attained by proportioning the degree of vacuum on the respective table sections as the sections 40, 41, and 42 are actuated between a holding function and an indexing function. That is, when the movable section is subjected to full negative pressure as during an indexing step, the stationary sections 40-and 41 are operated to impart a lesser negative pressure thereon, e.g., a l-50 percent negative pressure. Conversely during a holding operation, the movable section 42 is subjected to a lesser negative pressure, e.g., -50 percent as the stationary sections 40 and 41 are subjected to a full or 100 percent negative pressure. Thus by maintaining the respective sections under relative negative pressures, while full negative pressure is imparted to the operating sec tions, any tendency of the material to shift relative to the blanket is prohibited. As a result accurate registration of print is insured.

FIGS. 13 to 16 illustrate a modified form of the invention. In this form of the invention the apparatus 100 comprises a frame means 101 similar to that described with respect to FIGS. 1 to 5.However, in this form of the invention the table means 102 comprises a unitary structure comprising a table top surface 102A which extends substantially the width-and lengthof the frame means 101. Beneath the table top surface 102A is a vacuum chamber 103 which is suitably connected in communication to a vacuum pump 104 for drawing a negative pressure on the table surface during the opera-' tion of a screen printing operation as will be hereinafter described. As seen in FIGS. 16 & 18 the table surface 102A is preferably formed with a series of spaced longitudinally extending ridges 1023 the apexes of which provide the support for an endless printing blanket 105 extending thereover. Also the table surface 102A is provided with a series of perforations or openings 106 in communication with the vacuum chamber 103 beneath the table surface 102A. The openings 106 may be located in the valleys between adjacent ridges 1028.

As previously described the endless printing blanket 105 is suitably threaded over end rollers, e.g., roller 107 rotatably joumalled at the opposed ends of the machine frame 101. The printing blanket is also provided, as previously described, with a series of perforations 105A extending therethrough to communicate with the perforations 106 formed in the table surface. In operation, as previously described, it will then be apparent that whenever a vacuum or negative pressure is pulled on the vacuum chamber 103 by operation of pump 104, that the blanket 105 and any non-porous material 108supported on the printing blanket 105 will be drawn and held fast to the table surface 102A.

In this form of the invention idexing of the printing blanket 105 and the material 108 supported thereon is effected by a positive drive of one of the end rollers, e.g., roller 107, over which the printing blanket 105 is threaded. As best seen in FIGS. 13 and 14 the driving roller 107 for the printing blanket 105 is rotatably journalled on a shaft 109 which is suitably joumalled in end bearings 110 supported on the frame means 101 of the apparatus 100. Fixedly connected to shaft 109 is a collar 111 to which there is secured a driving disk 112. As noted in FIG. 14 the driving disk 112 is secured to a lateral flange portion 111A of the collar 111 by means of a plurality of circumferentially spaced bolts 1 13. As described, the disk 112 is mounted on shaft 109 to rotate therewith, and with the end roller :01 supported thereon.

Rotatably joumalled on the roller shaft 109 adjacent the driving disk is a driving gear 114. The driving gear 114 is mounted on shaft 109 to rotate relative thereto.

Connected to the-gear to extend to one side thereof by asuitable bracket 115 is aclutch-means 116 which when operative connects the driving disk 112 into drivated, the driving disk 112 disposed between the operating pistons of the clutch, is connected in driving relationship to the driving gear causing the shaft 109 and the end roller 107 thereon to rotate therewith.

A second clutch or brake means is fixedly connected to the frame portion 119 of the machine. As best seen in FIG. 13 the second mentioned clutch or brake means 118 is similar in construction to clutch means 116. The arrangement is such that the brake means 118 is operatively connected in circuit with clutch means 116 so as to be alternately actuated. That is when clutch means 1 16 is rendered operative, the brake 1 18 is inoperative. And conversely when the brake 118 is operative, the clutch means 116 is inoperative The drive means, or power source to effect the drive of the gear 1 14 comprises a piston and cylinder assembly 119; the cylinder portion 119A of which is suitably secured to the frame 101 of the machine. The piston means of the assembly 119 includes a piston rod 120 arranged to extend beyond both ends of the cylinder 119A with the piston 121 of the assembly fixed intermediate the ends of the piston rod 120 within the cylinder 119A. One end of the piston rod 120 is connected to a rack 122 having a gear sector disposed in meshing relationship with the gear 1 14. The other end of the piston rod 120 is connected to an indexing adjusting means 123 whereby the displacement of the piston rod 120 determines the length of repeat or index,,as will be hereinafter described. I

The indexing adjusting means 123 comprises a stop 124 which is slidably mounted in a suitable track 125 on the frame 101 of the machine. An adjusting screw 126 is suitably threaded to stop assembly so that an operator, by manually turning the screw handle 127, can readily adjust the position of the stop 124 longitudinally of the frame. A pair of set screws 128 fixedly secures the stop 124 in the adjusted position. It will be understood, that by setting the stop 124 along the frame 101, within the range of the adjusting screw 126 that the stroke of the piston and consequently linear displacement of the rack 122 can be readily determined. By determining the linear travel of the rack 122, the angular travel of the end roller 107 and the printing blanket threaded thereover is likewise determined, thereby determining the linear distance or displacement of the blanket to define the repeat.

Secured to the piston rod is a bridge 130 which is adapted to move with the piston rod 120 whenever the piston and cylinder assembly is actuated. Mounted on the bridge 130 in space relationship are a pair of opposed deceleration cams 131, 132 which are arranged to actuate a deceleration valve 131A, 132A located on the machine frame adjacent the opposed limits of travel of the piston rod 120.

As best seenin FIGS. 13 and 15 the valve'stem of the deceleration valves 131A and 132A have connected to the upper end thereof, a cam roller 133, 134 which is adapted to engage the inclined cam surface of the cams 131, 132. The respective cams 131, 132 are adjustably mounted on the bridge 130 so that the angle or slope thereof may be changed depending on linear adjustment of the indexing means so as to activate the deceleration valves 131A, 132A, at a predetermined instance. The respective deceleration valves 131A, 132A are operatively connected in circuit to effect a gradual deceleration of the movement of the piston actuation to prohibit unnecessary banging of the moving components of the machine.

To stabilize the operation of the deceleration means and to counterbalance the torque as the deceleration cams 131, 132 ride over the respective deceleration valves 131A, 132A, an outrigger arm 137 is connected to the bridge 130. Connected to the end of the outrigger arm 137 is a roller 138 disposed in rolling engagement with a rail 139 extending along the machine frame 101. Thus, as best seen in FIG. 15, the end of the outrigger arm riding on rail 139 will counterbalance any tendency of the bridge to rotate as the cams 131 and 132 ride over their respective valves 131A, 132A.

To minimize the back lash between the meshing driving gear 114 and rack 122, a complementary rack section 122A is operatively associated with rack 122 so as to be adjustably displaced relative to rack 122. As best seen in FIG. 14 complementary rack segments 122A are disposed to either side of the driving rack 122. The complementary rack sections 122A are adjusted relative to the driving rack 122 by means of an adjusting screw 135. To minimize the back lash due to wear or working tolerances, the complementary sections 122A, 122A are adjusted relative to the drive rack 122, by effecting adjustment of the complmentary sections 122A, 122A to take up the back lash between the gear 114 and the rack means 122.

The construction and operation of the printing head, the screens carried thereby, the associated squeegees, together with the heater constructions utilized in the modified apparatus described, is similar to that described with respect to FIGS. 1 through 12. Consequently the operation of the apparatus 100 as modified in accordance with FIGS. 13 to 14, is as follows:

The material 108, e.g., a non-porous sheet material, to be printed is positioned on the printing blanket and with the material in position thereon the vacuum pump 104 is operated to impart a vacuum pressure on the table means 102 to draw a negative pressure thereon. The amount of negative pressure produced is that sufficient to draw the printing blanket 105 to the table and to maintain the blanket 105 immobile during a printing operation. Because of the blanket perforations 105A, the sheet material placed thereon is likewise held fast to the blanket as the negative pressure is maintained in the table chamber 103. With the material 108 secured to the blanket 105 by negative pressure and the blanket in turn secured to the table top 102A the screen printing operation is affected in the manner hereandbefore described. That is, the screen and associated squeegee (not shown) are lowered onto the material and the squeegee is operated to effect relative movement between the squeegee and associated screen to effect the printing stroke. Upon completion of the printing stroke the printing head, together with the associated screen and squeegee, are moved to a raised, non-printing position. The raising of the printing head and associated screen and squeegee is similar to that here-and-before described with respect to FIGS. 5, 8, and 9. That is, the squeegees are first raised off their respective screens due to the built in lost motion as described. Thereupon the screen will follow the movement of the squeegee to a raised n0n-printing position. With the screen and squeegee moved off the material and raised to a non-printing position, the negative pressure operating in the table vacuum chamber 103 is partially released to permit the indexing step to occur.

That is to permit the printing blanket 105 and the material supported thereon to be advanced to the next station. lt has been discovered that optimum results can be obtained by maintaining partial vacuum pressure in the vacuum chamber during the indexing operation. Preferably the maintaining of a negative pressure of between 30 to 60 percent of the holding negative pressure has been found to produce optimum results during the indexing operation. Generally the partial negative pressure maintained during the indexing step must be such as to permit the drive means to effect the advance or indexing of the blanket and material over the table surface during the indexing step while at the same time insuring that the material is fixedly secured to the blanket as the blanket advances to insure optimum or positive color registration. Y

To effect the indexing operation in the apparatus, the valve controlling fluid flow to the piston and cylinder assembly 119 is actuated to effect displacement of the piston rod 120 to the right as viewed in FIG. 13. Displacement of the piston rod 120 to the right effects corresponding displacement of the rack 122 which in turn drives the driving gear in a counterclockwise rotation as indicated in FIG. 13. The arrangement is such that the clutch 116 connected to the gear 114 is connected in circuit to be first actuated to clamp the driving disk 112, in driving relationship to the driving gear 114 and associated end roller 107 before the rack 122 is actuated; as the stationery braking means 1 18 is maintained in an open or inoperative position. Consequently when the rack 122 is actuated or displaced to the right, as viewed in FIG. 13, the driving gear 114 meshing therewith and driving disk 112 clamped thereto effects 'rotation of the end roller 107 causing the blanket 105 threaded thereon to be advanced in the direction of repeat a distance equal to the repeat distance as determined by the limiting adjusting means 123 operating on the drive cylinder and piston assembly 1 19. As the cam means 132 carried on the bridge of the piston 120 approaches the limit of the repeat, it actuates a deceleration valve 133 which decelerates the moving parts of the machine to prohibit unnecessary banging. As the indexing of the printing blanket 105 in the direction of repeat is terminated, the operation or cycling of the clutch 116 and the brake 118 is reversed whereby the fixed brake 118 is actuated to grip the driving disk 112 as the clutch 116 is released permitting the rack 122 to return to its normal position without effecting rotation of the end roller 107 and the printing blanket 105 thereover. Accordingly, upon completion of the indexing step as described, the screen printing cycle is repeated for effecting the next adjacent print.

It will be understood that the operation of the heaters in the modified embodiment is similar to that previously described. That is that as the blanket 105 and material 108 supported thereon is advanced in the direction of the index, the screen, associated squeegee, and the connected heater is moved relative thereto so that the heater is positioned in heat transfer relationship to the trailing marginal portion of the printed portion of the material to effect the drying thereof so as to prohibit any smearing or smudging of the printed material during the next succeeding print. As the printing stroke of the next succeeding print is occurring, the heater is disposed in heat transfer releationship to the remaining portion, or undried portion of the preceding print to effect the drying thereof. As previously described the drying of a given print occurs in two steps. That is, a marginal portion thereof is dried during the indexing step, and the remaining portion of the print is dried during the printing stroke of the next succeeding print.

The basic distinctions between the apparatus embodiment of FIGS. 1 to 12 and embodiments 13 to 15 resides in the provision wherein the table means of the modified embodiment of FIGS. 13 to 15 comprises a unitary table structure having a rippled perforated surface to minimize friction between the moving blanket and the table means 102 during an indexing opera tion. Further that the indexing of the modified arrangement is effected by a positive drive means operating on the end roller 107 to effect indexing of the blanket 105 to advance the material the necessary repeat distance to effect succeeding screen prints on a continuous web of material.

While the present invention has been described with respect to several embodiments thereof it will be readily appreciated and understood that variations and modifications may be made without departing from the spirit or scope of the invention.

What is claimed is: l. A method of screen printing sequential complementary designs on a continuous strip of material comprising the steps of disposing a dryer in adjacent tandem relationship to a printing screen having a design portion disposed between opposed well portions with an associated sqeegee, positioning the, screen into printing position on the material to be printed,

effecting the printing of said design on the material by relative movement of the squeegee over the design portion of the screen,

raising the screen and associated squeegee off the material subsquent to the printing thereof to a nonprinting position, i

indexing said printed portion of said material in the direction of index a distance equal to the size of the printed portion and retracting said screen and associated squeegee in the non-printing position and the dryer in a direction opposite to the indexing of said printed portion to dispose the dryer over a trailing portion of said printed portion when the screen is in the retracted non-printing position,

returning said screen and associated squeegee together with the dryer to printing position for effecting the printing of the next adjacent design, thereby positioning said dryer in drying relationship to another portion of said first printed portion to efi'ect the drying thereof as the next succeeding design is being printed.

2. The method as defined in claim 1 wherein said indexing ofthe printed material and the retracting of said screen and dryer in the non-printing position relative to one another is effected simultaneously..

3. A method of screen printing sequential complementary designs on a continuous strip of material comprising the steps of:

coupling a dryer in tandem to a printing screen hav-' ing a printed portion and opposed well portions with an associated squeegee,

positioning the screen onto the material to be printed whereby the squeegee is initially disposed in one of the well portions,

effecting the printing of said material by transversing" said squeegee over the printed portion of said screen, 

1. A method of screen printing sequential complementary designs on a continuous strip of material comprising the steps of disposing a dryer in adjacent tandem relationship to a printing screen having a design portion disposed between opposed well portions with an associated sqeegee, positioning the screen into printing position on the material to be printed, effecting the printing of said design on the material by relative movement of the squeegee over the design portion of the screen, raising the screen and associated squeegee off the material subsquent to the printing thereof to a non-printing position, indexing said printed portion of said material in the direction of index a distance equal to the size of the printed portion and retracting said screen and associated squeegee in the nonprinting position and the dryer in a direction opposite to the indexing of said printed portion to dispose the dryer over a trailing portion of said printed portion when the screen is in the retracted non-printing position, returning said screen and associated squeegee together with the dryer to printing position for effecting the printing of the next adjacent design, thereby positioning said dryer in drying relationship to another portion of said first printed portion to effect the drying thereof as the next succeeding design is being printed.
 2. The method as defined in claim 1 wherein said indexing of the printed material and the retracting of said screen and dryer in the non-printing position relative to one another is effected simultaneously.
 3. A method of screen printing sequential complementary designs on a continuous strip of material comprising the steps of: coupling a dryer in tandem to a printing screen having a printed portion and opposed well portions with an associated squeegee, positioning the screen onto the material to be printed whereby the squeegee is initially disposed in one of the well portions, effecting the printing of said material by transversing said squeegee over the printed portion of said screen, raising the scrEen and associated squeegee off the material subsequent to the printing thereof to a non-printing position, indexing said printed material a predetermined distance, moving said screen and associated dryer in a direction opposite to the indexing direction of said printed portion to position the dryer over the trailing edge portion of said preceding print whereby said dryer effects the drying of said trailing edge portion, returning said screen and associated dryer to its initial position, lowering said screen into printing position for effecting the printing of the next adjacent design whereby said associated dryer is in position for effecting the drying of the leading edge portion of said preceding printed portion, and effecting the printing of the next adjacent repeat as said leading portion of the preceding print is being dried.
 4. The method as defined in claim 3 wherein said screen is raised and lowered independently of said dryer between printing and non-printing positions.
 5. The method as defined in claim 3 wherein said screen in the printing position overlies a marginal portion of the preceding printed repeat on said strip of material.
 6. An apparatus for screen printing continuous sequential designs on an elongated strip of material comprising: a frame means, support means on said frame means for supporting thereon the material to be printed, a printing head means movably mounted on said frame means, a printing screen having opposed well portions and an associated squeegee mounted on said printing head means for movement between an operative printing position wherein said screen is placed onto said material, and an inoperative non-printing position wherein said screen is raised off the material, elevating means for effecting the raising and lowering of said printing head and associated screen between printing and non-printing positions, a dryer means connected in tandem to said screen, operating means for effecting relative movement between said squeegee and associated screen to effect the printing stroke in the printing position of said printing head, indexing means for indexing said material subsequent to the printing stroke, and drive means for effecting the drive of said printing head and associated screen and connected dryer means in a direction opposite to the direction of said index to position said dryer means in drying relationship to the trailing portion of the indexed printed portion to effect a positive drying of said trailing portion prior to effecting the next succeeding print.
 7. The apparatus as defined in claim 6 wherein said support means comprises: a table means mounted on said frame, said table means including a first portion fixed to said frame, and a second portion operatively connected to said frame for reciprocal movement relative to said first fixed portion, each of said table portions including adjacent co-planar perforated table tops having a vacuum chamber operatively connected to each of said tops, means for drawing a negative pressure on each of said chambers, and said indexing means including a table driving means operatively connected to said second portion for effecting the advancement of the printed material a predetermined repeat.
 8. The apparatus as defined in claim 7 and including: end rollers mounted on said frame at opposite ends of said table means, an endless printing blanket threaded over said end rollers, said blanket having its upper flight supported on said table tops, said blanket having a series of perforations formed thereon.
 9. The apparatus as defined in claim 6 wherein said printing head comprises: a lower head assembly and an upper head assembly, means for slidably supporting said upper head assembly on said lower head assembly for relative linear movement therebetween, said elevating means being operatively connected to said lower head assembly, and said screen being sUpported on said upper head assembly.
 10. The invention as defined in claim 9 wherein said drive means comprises: a printing head carriage reciprocally mounted on said frame means, means connecting said printing head to said printing head carriage, and a power means for effecting the drive of said priting head carriage and said printing head.
 11. The invention as defined in claim 10 wherein said operating means is carried on said printing head carriage.
 12. The invention as defined in claim 6 and including means for pivoting said dryer between operative and inoperative position.
 13. The invention as defined in claim 7 and including means for adjusting the relative position of said table tops.
 14. An apparatus for screen printing sequential designs on a continuous strip of material comprising: a frame means, a blanket movably mounted on said frame, said blanket defining a support for the material to be printed, a printing head mounted on said frame for relative movement with respect thereto, said printing head including a screen and an associated squeegee mounted for movement thereon between a raised non-printing position and a lowered printing position, and means for effecting relative movement of said screen and associated squeegee for effecting a printing of the material when said screen is disposed in the printing position onto said material, a drying means connected to said screen for movement therewith, means for indexing said blanket and material supported thereon a predetermined distance after a printing operation, and means for effecting a reciprocating drive of said printing head to retract said printing head in a direction opposite to the indexing of said blanket and material when the screen is disposed in a non-printing position to position the connected drying means in drying relationship to the trailing marginal portion only of the indexed printed portion of the material and to return said printing head to printing position to position the connected dryer means in drying relationship with another portion of said index printed portion when the screen and associated squeegee is effecting the next succeeding print.
 15. The invention as defined in claim 14 wherein said means for indexing said blanket and material thereon after a printing operation includes: a table mounted on said frame means, said table including a first portion fixed to said frame means, and a second portion mounted for reciprocal movement relative to said first portion, each of said first and second table portions having coplanar table tops, means defining a vacuum chamber adjacent each of said table tops, means for alternately drawing a negative pressure on each of said table top chambers, and a table driving means connected to said second table portion for effecting the reciprocal movement thereof to effect the indexing of said blanket when said second portion is subjected to said negative pressure.
 16. An apparatus for screen printing continuous sequential designs on elongated strips of material comprising: a frame, a table means mounted on said frame, said table means including a first portion fixed to said frame, and a second portion operatively connected to said frame for reciprocal movement relative to said first fixed portion, each of said table portions including adjacent co-planar perforated table tops having a vacuum chamber operatively connected to each of said tops, means for drawing a negative pressure on each of said chambers, a table drive means connected to said second table portion for effecting the movement thereof relative to said first portion for effecting indexing of the printed material, end rollers mounted on said frame at opposite ends of said table means, an endless printing blanket threaded over said end rollers, said blanket having its upper flight supported on said table tops, said blanket having a series of Perforations formed thereon, a printing head, said printing head including a an upper head assembly and a lower head assembly, means for slidably supporting said upper head assembly on said lower head assembly for permitting relative reciprocal movement therebetween, means operatively connected to said lower head assembly for effecting the raising and lowering of said printing head relative to said blanket between a printing and non-printing position, at least one printing screen mounted on said upper head assembly for movement between printing and non-printing position therewith, a sqeegee means operatively associated with said printing screen, squeegee drive means for effecting relative movement between said squeegee and said screen to effect a printing stroke, a dryer means operatively connected to said screen, a printing head drive means operatively connected to said printing head for effecting the movement of said printing head, associated screen and connected dryer in a direction opposite to the direction of index, said printing head drive means including a printing head carriage reciprocally mounted on said frame, means operatively connected said printing head to said carriage means, and a power means connected to said printing head carriage to effect the reciprocal movement thereof, said squeegee drive means including a piston and cylinder assembly carried on said printing head carriage.
 17. A method of screen printing successive abutting designs on a continuous strip of sheet material comprising the steps of positioning a printing screen having an associated squeegee and dryer into a printing position onto the material to be printed, effecting the printing of said material by relative movement between the squeegee and the associated screen, raising the screen and associated squeegee from the material subsequent to the printing thereof to a non-printing position, shifting the screen and associated dryer in an opposite direction relative to the printed portion of the material as the latter is indexed to position the dryer in heat transfer relationship to a trailing portion of said printed material between successive printing operations, and repositioning said screen and associated squeegee and dryer in printing position upon the indexed material to effect the next adjacent print and thereby positioning said dryer in heat transfer relationship to the remaining portion of the preceding print to complete the drying of said preceding print.
 18. An apparatus for screen printing comprising: a frame means, a support means on said frame means for supporting thereon the material to be printed, said support means including means for securing the material to be printed thereto, a printing head means movably mounted on said frame, a stencilled screen and an associated squeegee carried on said printing head, elevating means operatively connected to said printing head for effecting the raising and lowering of said printing head means and associated screen and squeegee carried thereon between printing and non-printing position, a dryer means connected to said screen to move therewith, operating means for effecting relative movement between said squeegee and associated screen to effect a printing stroke in the printing position of said screen, indexing means for indexing said support means and material there-on a distance equal to the length of the printed design, and said support means comprising: an endless printing blanket, and said indexing means comprises: an end roller over which said blanket is threaded, and a unidirectional drive means connected in driving relationship with said end roller for effecting the indexing of said blanket, wherein said unidirectional drive means includes: a driving disk connected in driving relationship with said end roller, a driving gear rotatably journalled for relative rotation wIth respect to said driving gear, means for releasably coupling said driving gear into driving relationship with said driving disk, and drive means operatively connected to said driving gear to effect the drive thereof when coupled to said driving disk.
 19. The invention as defined in claim 18 and including means to limit the angular rotation of said end roller to determine the index distance.
 20. The invention as defined in claim 18 wherein said drive means includes: a piston and cylinder assembly having a reciprocating piston, and a rack disposed in meshing relationship with said driving gear to effect the drive thereof when said piston and cylinder assembly is actuated.
 21. The invention as defined in claim 20 and including means to prohibit back lash between said driving gear and rack meshing therewith.
 22. In a screen printing apparatus having an endless printing blanket for supporting the material to be printed, and a printing screen and associated squeegee the improvement of: an indexing means for effecting the movement of said blanket in the indexing direction, said indexing means including an end roller over which said blanket is threaded in driving engagement therewith, drive means for effecting the drive of said roller to effect the drive of the blanket threaded thereover, and limit means for limiting the angular rotation of said end roller to determine the distance through which said blanket is displaced, said drive means being unidirectional, wherein said drive means comprises: a driving disk connected to said end roller to rotate therewith, a driving gear mounted for relative rotation with respect to said driving disk, means for releasably coupling said gear in driving relationship with said driving gear, and a rack means disposed in meshing relationship with said gear to effect the drive thereof.
 23. The invention as defined in claim 22 wherein said rack means includes means for prohibiting back lash between said gear and rack means meshing therewith.
 24. The invention as defined in claim 22 and including a power means to effect linear displacement of said rack means.
 25. The invention as defined in claim 24 wherein said limit means includes adjustable stops to determine the linear displacement of said rack means.
 26. The invention as defined in claim 24 wherein said power means includes a piston and cylinder assembly operatively connected to said rack means.
 27. An indexing assembly for use in a screen printing machine having an endless printing blanket for supporting the material to be printed comprising: an end roller over which said blanket is threaded, means for securing the material to be printed on said blanket, means for effecting unidirectional drive of said roller to advance said blanket in the direction of index, and means for limiting the movement of said blanket in the direction of index to determine the index distance, wherein said unidirectional drive means comprises means for engaging and disengaging the drive of said end roller, wherein said latter means comprises: a driving disk connected to said end roller to rotate therewith, and a pair of alternately activating gripper means operatively associated with said driving disk whereby actuation of one of said gripper means functions to effect the drive of said disk in the direction of index, and the alternate actuation of the other disk functions to secure said disk and associated end roller in the indexed position thereof.
 28. The invention as defined in claim 27 and including: a driving gear mounted for relative rotation with respect to said disk, a rack disposed in meshing relationship with said gear to effect the drive thereof, and a power means operatively connected to said rack for effecting the displacement thereof.
 29. The invention as defined in claim 28 and including means to minimize back lash between said gear and aSsociated rack.
 30. The invention as defined in claim 29 said latter means including a complementary rack segment adjustably disposed relative to said rack.
 31. The invention as defined in claim 28 wherein said power means comprises a piston and cylinder assembly including a piston rod having one end thereof operatively connected to said rack to effect the linear displacement thereof.
 32. The invention as defined in claim 28 wherein one of said gripper means is mounted on said gear to couple said disk in driving relationship therewith when actuated, and said other of said gripper means being fixedly secured to maintain said disk in the rotated position thereof when actuated to permit the return of said rack and associated gear to its original position. 